The Secret Conversations Of Plants

Mar 13, 2017

You may not realize it but the soil is buzzing with conversation. Plants talk to one other. Some conversations are nice and others are nasty.

Through a fungal network plants can warn each other of pending attacks by bacteria or bugs or they can  send herbicides they manufacture to kill other plants.

(from left) Xavier graduate Kira Liggins and Assistant Biology Professor Dr. Kat Morris.
Credit Ann Thompsonj / WVXU

Xavier University Assistant Professor of Biology Dr. Kathryn Morris and her students are studying these underground conversations. She says, "Every system that we've looked at, every plant or chemical interaction shows these fungal strings are really important for mediating plant communication."

She has connected pots with PVC pipes. One side has corn and the other has tomato plants. A square piece of mesh allows the fungus to link the roots of the two pots.  "There is a huge variety and they are constantly talking to each other above ground and below ground." she says. "I think it's a very noisy environment of conversation that we just don't pay attention to."

But people are starting to pay attention, like the BBC.

These conversations are hard to study because the fungus is eaten in a matter of hours by bacteria and if you disrupt the fungus it dies.

Xavier graduate Kira Liggins had to look at it under a microscope. "We would plant a separate corn plant to see if the fungi were there. It was kind of cool taking the roots out and then actually looking under a microscope for the fungi." She and others subjected the plants to different scenarios, in one case spraying the plant with its own hormone to signal an attack.

Undergraduate Rachel Fletcher is involved with the project and wonders if the conversations of certain species are more sophisticated. "We do know there are more plants that have fungi, meaning they are more connected to have more messages or transfer more defense proteins to the soil."

Rachel Fletcher says the natural defenses of plants could have a significant environmental impact.
Credit provided

Both benefit. The fungus gets carbon from the plant and the plant gets water and nutrients from the fungus.

Understanding plant conversations appears to have environmental benefits. According to Morris, "So application of some of these hormones as protection instead of applying pesticides would be one application. Also, if we have communication that can be targeted where we have sets of plants that are talking to one another and leaving out other sets of plants, than that is an interesting way of pondering pest control options as well."

This story was originally published May 23, 2016.